Raspberry Pi added a feature in their firmware that restricts users from swapping RAM chips, sometimes even RAM chips of the same capacity from other Raspberry Pi boards. Apparently there were people buying cheap 1 or 2 gig Pi 5s, soldering in some cheap and sometimes unreliable 8 gig RAM chips, and selling them as new 8 gig Pi 5s. Now I totally understand where Raspberry Pi's coming from. They don't wanna support Pis being sold like this, because flaky RAM and dodgy resellers are a huge problem. Especially with how profitable can be in the current AI bubble.